The most common flexible leaflet valve construction includes three leaflets mounted to commissure posts around a peripheral non-expandable support structure with free edges that project toward an outflow direction and meet or coapt in the middle of the flowstream. A suture-permeable sewing ring is provided around the inflow end.
The most successful bioprosthetic materials for flexible leaflets are whole porcine valves and separate leaflets made from bovine pericardium stitched together to form a tri-leaflet valve. Bioprosthetic heart valves are packaged in jars filled with preserving solution for shipping and storage prior to use in the operating theater. To minimize the possibility of damage to the relatively delicate bioprosthetic heart valves, they are stabilized with bracketing structure to prevent them from striking the inside of the jar. The valves are stabilized with various structures, including a 2- or 3-piece clip and tubular sleeve structure, such as shown in U.S. Pat. No. 6,416,547 to Erickson, et al.
Bioprosthetic valves typically have a delivery holder centrally located and sutured thereto, and an elongated delivery handle couples to the holder for manipulating the valve assembly during implant. The holder is attached to the inflow sewing ring for mitral valves and to the inflow cusps or outflow commissure tips for aortic valves.
Mitral valve replacement is the most common when moderate to severe calcification is present on the leaflets. When implanting a valve in the mitral position the valve is inverted with the inflow side facing the surgeon. Due to this less visible and somewhat difficult implant configuration, ease of the implant and suturing procedure is more important.
When placing a tissue type prosthetic valve in the mitral position, the commissure posts are on the distal or blind side of the valve and may become entangled with pre-installed anchoring sutures, potentially damaging the annulus or tissue valve during delivery. Some attempts have been made to overcome these problems in current holders for prosthetic mitral valves. An example of such a holder is U.S. Pat. No. 4,865,600, Carpentier, et al., incorporated herein by reference, and another similar device is seen in U.S. Pat. No. 6,966,925 to Stobie which includes a shaft member positioned on the holder that is axially movable just prior to valve deployment to cause lengths of holder-valve attachment sutures to extend axially beyond the commissure posts in the fashion of a tent, thereby preventing looping of an array of pre-implanted anchoring sutures around the commissure posts.
Because of the complexity of certain bioprosthetic valve systems, there is a continued need in the art for enhancements to ease the use of such systems for the operating room staff and surgeon.